Storage Tank Insulation Joint Apparatus and Method

ABSTRACT

A joint for fluid storage tank insulation systems. A central expansion joint forms a fluid-sealed recessed channel having a ridge-like cap. Water and moisture are directed away from the central expansion joint by the ridge-like cap. Any water that breaches the cap enters the recessed channel and flows out of the expansion joint without damaging tank insulation material. With installations having multiple expansion joints, at least one of the expansion joints can be equipped with an inverted cap to form a gutter within such expansion joint.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation and claims the benefit of U.S. patentapplication Ser. No. 13/651,599, filed Oct. 15, 2012, which is anon-provisional application claiming the benefit of U.S. Prov. Pat. App.Ser. No. 61/549,956, filed Oct. 21, 2011, both of which are incorporatedfully herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to expansion joints for insulated fluidstorage tanks. More particularly, the present invention pertains toexpansion joints on thermally insulated fluid storage tanks. Moreparticularly still, the present invention pertains to a expansion jointson fluid storage tanks, including upper surfaces of said fluid storagetanks, and a method for installing such expansion joints.

2. Brief Description of the Prior Art

The installation and use of thermal insulation on storage tanks is wellknown. Such thermal insulation can be particularly beneficial on large,flat-bottomed tanks used for storing materials that are sensitive totemperature fluctuations. Among other benefits, the insulation acts toreduce heat loss or gain of the materials stored within such tanks.

Existing methods for insulating storage tanks frequently employinterlocking panels of insulation and jacketing material. In one commonmethod of insulating fluid storage tanks, a first layer of insulationpanels is installed on the outer surfaces of a storage tank. Thereafter,a second layer of jacketing material is installed around the insulationmaterial, encasing the insulation panels and securing such insulationpanels in place around such storage tank.

Such insulation and jacket panels, typically fabricated to fit thespecific dimensions of a particular storage tank, can frequently includeflanges that are mechanically connected to adjacent panels. In onecommon prior art method, mechanical seams are used to join adjacentpanels and create a homogeneous outer jacket that secures insulationpanels to a storage tank. Ideally, such panels prevent moisture ingress,provide wind resistance and thermal insulation, and have inherentexpansion and contraction properties to account for thermal expansionand contraction effects.

Depending on the operating temperature of a tank, as well as the ambienttemperatures in the environment surrounding such tank, tank insulationsystems may require installation of at least one expansion/contractionjoint (“expansion joint”), especially on the roof or upper surface(s) ofsuch tank. Such expansion joints absorb thermal expansion or contractionof the storage tank itself, as well as expansion and contraction ofinsulation materials and metal jacketing or cladding around such tank.

Such expansion joints are especially useful when installed on roofs orupper surface(s) of storage tanks because such areas can be particularlysusceptible to thermal expansion and contraction. However, existingexpansion joints are typically prone to water intrusion, as rain waterand/or moisture from other sources have a tendency to collect on theupper surfaces of storage tanks.

In most cases, roofs and other upper surface(s) of storage tanks aremanufactured using a number of steel sheets or other components that arewelded or otherwise jointed together to form a substantially continuoussurface. Although such steel sheets or other manufacturing componentsare generally rigid, and typically have at least a gentle slope from thecenter toward the outer edges of a roof to facilitate water drainage,low spots or depressions can nonetheless form at different places,particularly along the relatively large surface area of a tank roof;rain water and moisture from other sources can frequently collect andpond in such low spots. If an expansion joint happens to intersect or bein close proximity to such a low spot, water or moisture that collectsat such a low spot can enter the expansion joint. Even without such lowspots, driven rain and other precipitation can often directly invadeconventional expansion joints.

Water or moisture entering a conventional expansion joint can oftenintrude into the space formed between the outer surface of a storagetank and the inner surface of the insulation materials (typicallypanels) covering said tank. Such water or moisture frequently results inoxidation or corrosion of the storage tank. In many cases, water in thisspace can also flow outward off the upper surface of a tank, over theouter perimeter edge of the tank roof, and collect behind verticalinsulation panels disposed around the side walls of said tank. If enoughwater collects behind such insulation panels, the weight of such watercan cause a catastrophic failure of the insulation system and its meansof attachment to an underlying storage tank.

In an attempt to direct water away from expansion joints, prior artmethods have included the construction of raised dam-like features nearsuch expansion joints. In many cases, such dam-like features are formedby turning up panel ends near the expansion joint. Ideally, any watercollecting near an expansion joint will be prevented from entering suchexpansion joint by the raised dam-like members and, as a result, pondaway from the expansion joint and eventually run off or evaporate fromthe tank roof Additionally, elongate cap members (typically constructedof metal) are fabricated and installed over expansion joints. However,such efforts have proven to be ineffective at keeping water and moistureout of expansion joints, especially with respect to wind-drivenprecipitation or moisture.

Thus, there is a need for an improved expansion joint that beneficiallyprevents water (in the form of rain, precipitation or otherwise) andmoisture from entering such expansion joint and contacting insulationmaterials in proximity to said expansion joint. Said expansion jointshould prevent water and moisture from intruding into the spaces formedbetween insulation panels and the outer surface of a storage tank, aswell as spaces existing between insulation and jacketing materials.

SUMMARY OF THE PRESENT INVENTION

The expansion joint of the present invention provides a solution forkeeping liquids (water and/or moisture) entering such expansion jointisolated from insulation materials, as well as underlying storage tanksurfaces. Unlike prior art expansion joints that merely attempt toprevent water from entering said expansion joints, the expansion jointof the present invention comprises a channel that acts to collect anywater and moisture entering said expansion joint, and direct said waterand moisture away from said expansion joint.

In the preferred embodiment, the expansion joint of the presentinvention comprises a channel, fluid sealed with at least one flexibleimpermeable material (such as, for example, Thermoplastic Elastomer or“TPE”). Said expansion joint of the present invention can also bebeneficially covered by a metal expansion/contraction cap. Said channelis recessed relative to the surrounding insulation panels in order toallow any water that breaches the cap and enters the channel to flowwithin such channel, over the tank sidewalls and to away from said roofor upper surface.

The installation of a central expansion joint of the present inventioncan generally comprise the following basic steps:

Roof insulation panels (typically standing seam panels) are installed onthe upper surface of a tank roof. Opposing ends of said roof insulationpanels are spaced a desired distance apart, thereby forming asubstantially elongate gap between such panels. In the preferredembodiment, said gap extends substantially along the entire width ofsaid tank roof, and passes through the center point of said tank roof.Once said gap is formed, filler insulation material is then installed insuch gap. Said filler insulation material has a thickness that is lessthan the thickness of surrounding roof insulation panels, therebyforming a recessed channel within said gap. Said recessed channelextends substantially along the width of said tank roof.

An elongate strip of flexible and impermeable material such as TPE,ideally having reinforced edges, is installed within said recessedchannel along the length of said expansion joint. In the preferredembodiment, such reinforced edges comprise parallel concertina oraccordion-like aluminum members molded within said strip along both longsides of said TPE strip. The outer metal jacketing or cladding materialis then installed, such that said reinforced edges of said TPE strip arebeneficially inserted or sandwiched between the insulation material andouter metal jacketing. Although said strip member is described herein asbeing constructed of TPE material, it is to be observed that otherflexible and relatively impermeable materials can likewise be used forthis purpose.

Butyl tape is then installed on the bottom of a pre-manufacturedelongate metal expansion/contraction cap, and said cap is placed overthe expansion/contraction joint (that is, said elongate recessedchannel), notching out where required for individual seams. Fasteners(which can include, without limitation, pop rivets or the like) areinstalled along a desired spacing pattern to penetrate the metal cap,butyl tape, metal roof panel and reinforced edges of said TPE strip.

Although the above process can be employed at virtually any positionalong the roof or other upper surface of a storage tank, it isparticularly useful when utilized to install an expansion jointcentrally positioned on said roof or other upper surface of such tank.Additionally, an alternative embodiment outer expansion joint utilizesthe same basic design as a “central” expansion joint described above,except that the outer expansion/contraction metal cap member isessentially inverted and installed as a gutter to allow any roof waterto run to the outside of the tank roof In such alternative embodiment,edges or flanges of said metal cap member can be beneficially installedunder center roof panels, and over the outer roof panels, to providepositive water shed characteristics. Because a TPE strip is installedunder said inverted metal cap member, it serves as flashing to channelany water or moisture that might enter through the insulation systemaround the metal cap to the outside of the tank roof.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe preferred embodiments, is better understood when read in conjunctionwith the appended drawings. For the purpose of illustrating theinvention, the drawings show certain preferred embodiments. It isunderstood, however, that the invention is not limited to the specificmethods and devices disclosed. Further, dimensions, materials and partnames are provided for illustration purposes only and not limitation.

FIG. 1 depicts a side perspective and partial sectional view of aninsulated fluid storage tank.

FIG. 2 depicts a side sectional view of a “center” expansion joint ofthe present invention.

FIG. 3 depicts a side sectional view of an alternative embodiment“outer” expansion joint of the present invention.

FIG. 4 depicts an overhead view of a fluid storage tank equipped withthe center and outer expansion joints of the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring to the drawings, FIG. 1 depicts a side perspective and partialsectional view of an externally insulated fluid storage tank 100. Asdepicted in FIG. 1, said storage tank 100 is substantially cylindrical,and has a substantially flat roof or upper surface. As depicted in FIG.1, said storage tank 100 comprises substantially vertical side wall 101and substantially horizontal roof section 201. By way of illustration,but not limitation, said tank side wall 101 can be constructed of steelor other suitable rigid material having desired strength and othercharacteristics.

As depicted in FIG. 1, storage tank 100 includes an external insulationsystem. Said external insulation system generally comprises interlockingprefabricated insulation panels 110 and jacketing material 120. A firstlayer of insulation panels 110 having desired thermal insulation andother characteristics is installed around the outer surfaces of storagetank 100. Thereafter, a second layer of jacketing material 120 isinstalled around said insulation panels 110, encasing the insulationpanels 110 and securing such insulation panels in place around storagetank 100.

In the embodiment depicted in FIG. 1, mechanical seams 121 are used tojoin vertical jacket panels 120 and create a homogeneous outer jacketthat secures insulation panels 110 to storage tank 100. Ideally, suchjacket panels 120 prevent water/moisture ingress, provide windresistance, and have inherent expansion and contraction properties.

Referring briefly to FIG. 4, which depicts an overhead view of fluidstorage tank 100, said fluid storage tank 100 is equipped with anexternal insulation system generally comprising a first layer ofsubstantially vertical insulation panels 110 and a second, outer layerof substantially vertical metal panels 120. Said fluid storage tank 100is further equipped with a similar layer of insulation materials andmetal jacketing panels disposed on upper surface of roof 201 as morefully described herein.

FIG. 2 depicts a side sectional view of a “central” expansion joint 300of the present invention. Although said joint 300 (as well as outerexpansion joint 320 described below) is referred to herein as an“expansion” joint for ease of reference, it is to be observed that saidjoint 300 is also capable of accommodating contraction forces. Standingseam roof insulation panels 210 having a desired thickness are installedon the upper surface of a tank roof 201 with ends 210 a spaced a desireddistance apart to form an elongate gap at the desired location ofexpansion/contraction joint. Optional securement roof rods 202 can alsobe installed.

A section of insulation panel 211 is disposed in the gap formed betweenopposing ends 210 a of roof insulation panels 210. In the preferredembodiment, insulation 211 has a thickness less than the thickness ofroof insulation panels 210, thereby forming an elongate recessedchannel. In the preferred embodiment, insulation panel 211 hasapproximately one half of the thickness of adjacent insulation panels210.

In a preferred embodiment, elongate TPE (Thermoplastic Elastomer) strip230 having parallel reinforced side edge sections 231 is installed sothat a central portion of said strip 230 is received on panel 211 withinsaid recessed channel formed between opposing insulation panel members210. The longitudinal axis of said elongate TPE strip 230 issubstantially the same as the longitudinal axis of said recessed grooveformed between opposing insulation panels 210. As depicted in FIG. 2,said reinforced side edge sections 231 further comprise concertinashaped aluminum strip(s) molded within or securely attached to said TPEstrip 230, extending substantially along the entire length of said TPEstrip 230.

Reinforced side edge sections 231 of said strip 230 extend out of saidrecessed channel and lay on the upper surfaces of insulation panels 210on both sides of said recessed channel, along substantially the entirelength of said recessed channel. Metal roof jacket panels 220 areinstalled on the upper surfaces of said upper insulation panels 210,such that reinforced edge sections 231 of elongate TPE strip 230 arebeneficially received or sandwiched between insulation panels 210 and aportion of outer metal jacket panels 220.

Butyl tape 240 is installed on the upper surface of said metal jacketpanels 220, or the bottom of flange members 252 of elongate expansioncap 250. Thereafter, said cap 250 is installed the expansion joint ofthe present, notching out where necessary for individual seams of outermetal jacket panels 220. In the preferred embodiment, elongate cap 250has a substantially U-shaped or trapezoidal-shaped profile, extendinghigher than the surrounding insulation panels and jacketing panels, andallowing for expansion or contraction in a direction substantiallyperpendicular to the longitudinal axis of said elongate expansion cap250. Fasteners 260 (such as, for example pop rivets or threaded bolts)are installed along a desired spacing pattern to penetrate flangemembers 251 of cap 250, butyl tape 240, metal roof panel 220, andreinforced edge sections 231 of TPE strip 230. In the preferredembodiment, expansion cap 250 extends higher than the upper surfaces ofmetal roof jacket panels 220, thereby serving as a dam-like feature todirect liquids away from said expansion joint.

A watertight central expansion joint 300 as depicted in FIG. 2 canextend from side to side across the roof of a storage tank, typicallypassing through the center point of said tank. In many instances, thispath will be across the crest of said tank roof, such that saidexpansion joint will be sloped downward from said center point towardthe outer edges (sides) of said tank. As such, water entering saidexpansion joint drains away from the center of said roof, and toward theouter edges of said tank roof. Water not entering said expansion joint300 generally drains away from said expansion joint 300 in the directionof the arrows depicted in FIG. 2.

FIG. 3 depicts a side sectional view of an alternative embodiment“outer” expansion joint 320 of the present invention. Said “outer”expansion joint 320 is installed in essentially the same manner as thecentral expansion joint 300 described above. Namely, a section ofinsulation panel 211 is disposed in the gap formed between opposing ends210 a of roof insulation panels 210. As with a central expansion joint,insulation 211 has a thickness less than the thickness of roofinsulation panels 210, thereby forming an elongate recessed channel. Inthe preferred embodiment, insulation panel 211 has approximately onehalf of the thickness of adjacent insulation panels 210.

A flexible, impermeable strip is disposed within said recessed channel.In the preferred embodiment, an elongate TPE (Thermoplastic Elastomer)strip 230 having parallel reinforced side edge sections 231 is installedso that a central portion of said strip 230 is received on panel 211within said recessed channel formed between opposing insulation panelmembers 210. Said reinforced side edge sections 231 further compriseconcertina shaped aluminum strip(s) molded within or securely attachedto said TPE strip 230, extending substantially along the entire lengthof said TPE strip 230.

Reinforced side edge sections 231 of said strip 230 extend out of saidrecessed channel and lay on the upper surfaces of insulation panels 210on both sides of said recessed channel, along substantially the entirelength of said recessed channel. Metal roof jacket panels 220 areinstalled on the upper surfaces of said upper insulation panels 210,such that reinforced edge sections 231 of elongate TPE strip 230 arebeneficially received or sandwiched between insulation panels 210 and aportion of outer metal jacket panels 220.

Butyl tape 240 is installed on the upper surface of said metal jacketpanels 220. Thereafter, said cap 270 is installed over theexpansion/contraction joint, notching out where necessary for individualseams. Unlike cap 250 depicted in FIG. 2, which forms anupwardly-extending ridge or dam-like feature, cap 270 is substantiallyconcave in shape. As such, said cap 270 acts to form a gutter thatextends across substantially the entire width of a tank roof.

In the alternative embodiment depicted in FIG. 3, said expansion joint320 is typically installed on a sloped portion of a tank roof, with saidslope and water draining generally in the direction of the arrowsdepicted in FIG. 3. Accordingly, flat edges or flanges 271 of said metalcap member 270 can be beneficially installed (“tucked') under the edgesof roof panels 220 on the higher side of the tank roof, and over theedges of roof panels 220 on the lower side of the tank roof, to providepositive water shed characteristics. Because TPE strip 230 is installedunder said inverted metal cap 270, such TPE strip 230 serves as flashingto channel any water or moisture that might enter through the insulationsystem around the metal cap to the outside of the tank roof Fasteners260 (such as, for example pop rivets) are installed along a desiredspacing pattern to penetrate flanges 271 of cap 270, butyl tape 240,metal roof panel 220, and aluminum edge 231 of elongate TPE strip 230.

FIG. 4 depicts an overhead view of a fluid storage tank equipped with acentral expansion joint 300 and outer expansion joints 320 of thepresent invention, providing a system to accommodate tank roof expansionand contraction. Metal cap 250 forms a ridge that acts to direct wateroutward from a central expansion joint—that is, toward the outer rim ofa tank and away from said central expansion joint. However, in the eventthat any water should breach said cap 250 and enter said centralexpansion joint, the water enters an impermeable gutter (lined with TPEstrip 230) that carries such water out of the expansion joint and towardthe edges of the tank roof where it can harmlessly drain off of saidtank roof. Water on the tank roof that is directed away from saidcentral expansion joint by cap 250 can enter channels formed by invertedmetal caps 270 at outer expansion joints. Such water flows within saidouter channels to the outside of the tank roof where it also harmlesslydrains off of the tank roof.

The present invention is described herein primarily for use as a meansto account for thermal expansion/contraction of insulation materials onfluid storage tank roofs. However, it is to be observed that the presentinvention can also be used as a joint between insulation members, evenwhen such expansion/contraction is not encountered or is not asignificant concern. For example, the joint of the present invention canbe used as a beneficial means for splicing insulation materials on atank roof or other surface.

The above-described invention has a number of particular features thatshould preferably be employed in combination, although each is usefulseparately without departure from the scope of the invention. While thepreferred embodiment of the present invention is shown and describedherein, it will be understood that the invention may be embodiedotherwise than herein specifically illustrated or described, and thatcertain changes in form and arrangement of parts and the specific mannerof practicing the invention may be made within the underlying idea orprinciples of the invention.

What is claimed is:
 1. A joint between adjacent insulation members on anupper surface of a fluid storage tank, the joint comprising an elongatewatertight channel extending substantially across the entire uppersurface of the tank between the adjacent insulation members, the channelhaving an elongate strip of impermeable material disposed therein andextending out of the channel and laying on an upper surface of each ofthe adjacent insulation members.
 2. The joint of claim 1, furthercomprising an elongate cap disposed over substantially the entire lengthof the elongate channel, wherein the cap extends higher than theinsulation members.
 3. The joint of claim 1, wherein the elongatewatertight channel slopes toward at least one side of the fluid storagetank.
 4. The joint according to claim 1, wherein the joint is adapted tocontract in a direction substantially perpendicular to the longitudinalaxis of the elongate channel.
 5. The joint according to-claim 1, whereinthe joint is adapted to expand in a direction substantiallyperpendicular to the longitudinal axis of the elongate channel.
 6. Ajoint between adjacent insulation panels on an upper surface of a fluidstorage tank, the joint comprising: a recessed channel formed betweenthe insulation panels; and a strip comprising an impermeable materialand disposed within the channel along substantially the entire length ofthe channel.
 7. The joint of claim 6, further comprising a cap disposedover substantially the entire length of the channel and extending higherthan the insulation panels.
 8. The joint of claim 6, wherein theimpermeable material comprises a thermoplastic elastomer.
 9. The jointof claim 6, wherein the strip has a width greater than the width of thechannel.
 10. The joint of claim 9, further comprising jacketing materialdisposed on the insulation panels along the recessed channel, a firstside of the strip extending out of the channel and being secured to thejacketing material.
 11. The joint of claim 9, wherein the strip has atleast one reinforced edge.
 12. The joint of claim 6, wherein therecessed channel slopes toward at least one side of the fluid storagetank.
 13. The joint of claim 6, wherein the joint is adapted to contractin a direction substantially perpendicular to the longitudinal axis ofthe elongate channel.
 14. The joint of claim 6, wherein the joint isadapted to expand in a direction substantially perpendicular to thelongitudinal axis of the elongate channel.
 15. A method, comprising:forming an elongate recessed channel between a first insulation paneland a second insulation panel adjacent to the first insulation panel onan upper surface of a fluid storage tank; and installing in the recessedchannel a strip comprising an impermeable material and having a firstside that extends along substantially the entire length of the recessedchannel, the recessed channel and the strip cooperating to form a firstjoint between the first insulation panel and the second insulationpanel.
 16. The method of claim 15, further comprising installing anelongate cap over substantially the entire length of the recessedchannel, wherein the cap extends higher than the first insulation paneland the second insulation panel.
 17. The method of claim 16, whereinforming the recessed channel comprises forming the recessed channelacross the upper surface of the tank substantially from a first side ofthe storage tank to a second side of the storage tank opposite the firstside, and through the center of the upper surface; the method furthercomprising forming an outer expansion joint across the upper surface ofthe tank substantially from the first side of the storage tank to thesecond side of the storage tank and oriented substantially parallel tothe first joint by: forming a second recessed channel between the secondinsulation panel and a third insulation panel; installing in the secondrecessed channel a second strip comprising the impermeable material andhaving a first side that extends along substantially the entire lengthof the second recessed channel; and installing a second cap over thesecond strip and over substantially the entire length of the secondrecessed channel, wherein the second cap is inverted and forms a gutterwithin the second recessed channel.
 18. The method of claim 15, whereinthe first side of the strip further extends out of the channel, themethod further comprising: installing jacketing material on at least oneof the first insulation panel and the second insulation panel, proximateto the recessed channel; and securing the first side of the strip to thejacketing material along the recessed channel.
 19. The method of claim15, further comprising adapting the first joint to expand and contractin a direction substantially perpendicular to the longitudinal axis ofthe elongate channel.
 20. The method of claim 15, wherein forming therecessed channel comprises disposing a section of insulation panel in agap between opposing ends of the first insulation panel and the secondinsulation panel, the section of insulation panel having a thicknessless than the thickness of the first insulation panel and the secondinsulation panel.